This invention relates in general to valves utilized as part of an emergency shut down system in industrial processes, and in particular to a dual port block valve system that continuously cycles two valves between the open and closed positions, and enables the operator to know if there is a problem with operation of the valve prior to its needed use in an emergency shutdown.
Industrial operations often include block valves that are utilized as part of an emergency shut down system. One of the problems with these valves is the infrequency of their use, which may result in a "frozen" valve, at the critical moment when it is needed. However, frequent testing of the valve in insure that it is not frozen, or in some manner not working properly is usually not an option, due to the disruptions of the process caused by operating block valves in process lines.